Actually, because of the "rent seeking" of using politics to artificially constrain supply creating artificial scarcity, their property is valued much more than it should be valued without the market inefficiency. So, yes, their property values will fall because they were artificially inflated. The same happened to NYC Taxi Medallion owners where each medallion had a market value of $1.2 million because of the artificial limit of medallions and once Uber came along, the value dropped to $700,000.

Similarly, billionaire developers like Donald Trump will see his property values drop but that is only because they were artificially inflated.